Trial Outcomes & Findings for MICRO Study: Detecting Bacterial Infections Related to Orthopaedic Surgical Implants (NCT NCT03132246)

NCT ID: NCT03132246

Last Updated: 2020-05-15

Results Overview

A high level of absorbance via ELISA (greater than 1.5 ratio compared to control human serum) is a positive test result. The rate of not infected patient samples that return positive will demonstrate the false positive rate of the test.

• Recruitment status: COMPLETED
• Target enrollment: 260 participants
• Primary outcome timeframe: 1 year of clinical follow-up
• Results posted on: 2020-05-15

Participant Flow

Patients were enrolled if presented as high risk but later separated into the Infected Group or the Not Infected Group based on whether or not they went on to develop an infection post surgery. Group assignment is unknown for patients that did not complete the study and therefore groups are combined for reporting overall study numbers.

Participant milestones

Measure	Enrolled Trauma patients that were considered at risk for infection after fracture fixation. Inclusion criteria included open fractures, proximal tibia fractures, pilon fractures, and calcaneus fractures treated with surgical fixation. Each patient enrolled in the study provided 1-3 blood samples. These blood samples were tested using basic science techniques to determine the level of exposure to a staphylococcal biofilm each patient has experienced over a period of time. The only intervention patients experience are non-standard of care blood draws. The blood is then tested in a basic science laboratory. Patients were enrolled if presented as high risk but later separated into the Infected Group or the Not Infected Group based on whether or not they went on to develop an infection post surgery. Group assignment is unknown for patients that did not complete the study and therefore groups are combined for reporting overall study numbers.
Overall Study STARTED	260
Overall Study COMPLETED	156
Overall Study NOT COMPLETED	104

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Race and Ethnicity were not collected from any participant.

Baseline characteristics by cohort

Measure	Infected n=20 Participants Trauma patients that were considered at risk for infection after fracture fixation. Inclusion criteria included open fractures, proximal tibia fractures, pilon fractures, and calcaneus fractures treated with surgical fixation. All patients in this arm went on to develop an infection. Each patient enrolled in the study provides blood samples up to 10 times. These blood samples are to be tested using basic science techniques to determine the level of exposure to a staphylococcal biofilm each patient has experienced over a period of time. Blood draw: The only intervention patients experience is a non-standard of care blood draw. The blood is then tested in a basic science laboratory.	Not Infected n=136 Participants Trauma patients that were considered at risk for infection after fracture fixation. Inclusion criteria included open fractures, proximal tibia fractures, pilon fractures, and calcaneus fractures treated with surgical fixation. All patients in this arm did not go on to develop an infection. Each patient enrolled in the study provides blood samples up to 10 times. These blood samples are to be tested using basic science techniques to determine the level of exposure to a staphylococcal biofilm each patient has experienced over a period of time. Blood draw: The only intervention patients experience is a non-standard of care blood draw. The blood is then tested in a basic science laboratory.	Total n=156 Participants Total of all reporting groups
Age, Continuous	45 years n=20 Participants	44 years n=136 Participants	44 years n=156 Participants
Sex: Female, Male Female	5 Participants n=20 Participants	51 Participants n=136 Participants	56 Participants n=156 Participants
Sex: Female, Male Male	15 Participants n=20 Participants	85 Participants n=136 Participants	100 Participants n=156 Participants
Race and Ethnicity Not Collected	—	—	0 Participants Race and Ethnicity were not collected from any participant.
Body Mass Index	27 kg/m2 n=20 Participants	28 kg/m2 n=136 Participants	28 kg/m2 n=156 Participants
Smoker	12 Participants n=20 Participants	55 Participants n=136 Participants	67 Participants n=156 Participants
Follow up	58 months n=20 Participants	28 months n=136 Participants	43 months n=156 Participants
Time to Infection	11 months n=20 Participants • This measure is only valid for infection patients.	—	11 months n=20 Participants • This measure is only valid for infection patients.
Open Fracture	8 Participants n=20 Participants	51 Participants n=136 Participants	59 Participants n=156 Participants
Closed Fractures	12 Participants n=20 Participants	85 Participants n=136 Participants	97 Participants n=156 Participants

PRIMARY outcome

Timeframe: 1 year of clinical follow-up

Population: One to three blood sample tests were taken for each participant prior to the one-year post-operative clinical follow-up. Clinical cultures will also be monitored for the one-year post-operative period and compared to the blood sample test results to determine if the test is able to identify patients with positive staphylococcal infection cultures.

A high level of absorbance via ELISA (greater than 1.5 ratio compared to control human serum) is a positive test result. The rate of not infected patient samples that return positive will demonstrate the false positive rate of the test.

Outcome measures

Measure	Infected n=52 blood draw samples Trauma patients that were considered at risk for infection after fracture fixation. Inclusion criteria included open fractures, proximal tibia fractures, pilon fractures, and calcaneus fractures treated with surgical fixation. All patients in this arm went on to develop an infection. Each patient enrolled in the study provides blood samples up to 10 times. These blood samples are to be tested using basic science techniques to determine the level of exposure to a staphylococcal biofilm each patient has experienced over a period of time. Blood draw: The only intervention patients experience is a non-standard of care blood draw. The blood is then tested in a basic science laboratory.	Not Infected n=145 blood draw samples Trauma patients that were considered at risk for infection after fracture fixation. Inclusion criteria included open fractures, proximal tibia fractures, pilon fractures, and calcaneus fractures treated with surgical fixation. All patients in this arm did not go on to develop an infection. Each patient enrolled in the study provides blood samples up to 10 times. These blood samples are to be tested using basic science techniques to determine the level of exposure to a staphylococcal biofilm each patient has experienced over a period of time. Blood draw: The only intervention patients experience is a non-standard of care blood draw. The blood is then tested in a basic science laboratory.
Number of Blood Samples With High Levels of Absorbance Via ELISA for Patients (Greater Than 1.5 Ratio Compared to Control Human Serum)	48 blood draw samples	53 blood draw samples

SECONDARY outcome

Timeframe: 1 year of clinical follow-up

Population: One to three blood sample tests were taken for each participant prior to the one-year post-operative clinical follow-up. Clinical cultures will also be monitored for the one-year post-operative period and compared to the blood sample test results to determine if the test is able to identify patients with positive staphylococcal infection cultures.

A low level of absorbance via ELISA (greater than 1.5 ratio compared to control human serum) is a negative test result. The rate of infected patient samples that return negative will demonstrate the false negative rate of the test.

Outcome measures

Measure	Infected n=52 blood draw samples Trauma patients that were considered at risk for infection after fracture fixation. Inclusion criteria included open fractures, proximal tibia fractures, pilon fractures, and calcaneus fractures treated with surgical fixation. All patients in this arm went on to develop an infection. Each patient enrolled in the study provides blood samples up to 10 times. These blood samples are to be tested using basic science techniques to determine the level of exposure to a staphylococcal biofilm each patient has experienced over a period of time. Blood draw: The only intervention patients experience is a non-standard of care blood draw. The blood is then tested in a basic science laboratory.	Not Infected n=145 blood draw samples Trauma patients that were considered at risk for infection after fracture fixation. Inclusion criteria included open fractures, proximal tibia fractures, pilon fractures, and calcaneus fractures treated with surgical fixation. All patients in this arm did not go on to develop an infection. Each patient enrolled in the study provides blood samples up to 10 times. These blood samples are to be tested using basic science techniques to determine the level of exposure to a staphylococcal biofilm each patient has experienced over a period of time. Blood draw: The only intervention patients experience is a non-standard of care blood draw. The blood is then tested in a basic science laboratory.
Number of Blood Samples With Low Levels of Absorbance Via ELISA for Patients (Greater Than 1.5 Ratio Compared to Control Human Serum)	4 blood draw samples	92 blood draw samples

Adverse Events

Unmasked Non-completers

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Infected

Serious events: 0 serious events

Other events: 0 other events

Deaths: 1 deaths

Not Infected

Serious events: 0 serious events

Other events: 0 other events

Deaths: 3 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Dr. Aaron Johnson

University of Maryland School of Medicine

Phone: 410-328-1868

Email: ajohnson1@som.umaryland.edu

Results disclosure agreements

• Principal investigator is a sponsor employee
• Publication restrictions are in place